NEXON DIAGNOSTIC MANUAL

OSPREY- Application

DTC Troubleshooting Data

Version: 4.0

Date: 10-02-2017

Prepared by: Mithipati Prasad

Checked by: G S Raju / Senthilnathan S

Page: 192 of 654

TATA MOTORS Ltd.

This document must not be used in any way, such as copying and redistributing to third parties, without the consent of author.

P0255: IMV drive fault- Open Circuit

Overview:

DTC Description as per ISO standard

Injection Pump Fuel Metering Control “A” Intermittent (Cam/Rotor/Injector)

ECU Pin Number

Customer Symptom

Engine does not start.

Engine stops after few seconds.

Engine vibrates and makes noise

CE & MIL lamp is on.

Fault Effects (On Vehicle)

Reduced torque mode [Restricted performance

Disables the Pilot injection, Disables RVD, Disables EGR

IMV operates without trims, Cylinder balancing is deactivated.

High pressure Leak detection test is prevented.

IMV is fully open; System Pressure is limited to 800 bars.

Rail pressure build measurement is deactivated.

Disables the Rail pressure control fault detection.

Rail pressure will be set to 800 bar.

Lamp Status (If Any)

CE & MIL lamp is on

Fault Detection Condition

This DTC gets logged if IMV open circuit is detected.

Normal Operating Condition

Diagnostic tool display the IMV status at ignition ON

Probable Trouble Area

IMV, ECU, Wiring harness

Healing Condition

Clear the errors, Ignition OFF to ON, engine idle & fly-up condition

Component Details:

The Inlet Metering Valve controls rail pressure by regulating the amount of fuel sent to the pumping components of the HP

pump. This actuator has a double role as follows:

First it improves injection system output since the HP pump only compresses the amount of fuel needed to maintain the

rail pressure required by the system.

Secondly it reduces the temperature in the fuel tank as HP pump will be fed with the required amount of fuel for Engine

needs.

In fact, when excess fuel is sent to the return circuit, the expansion of the fluid (from rail pressure to atmospheric

pressure) involves a large amount of heat. This generates an increase in temperature of the fuel sent back to the tank.

Preliminary Checks

Check whether the customer voice / view about the issue is matching with the fault effects mentioned above. If

yes, go ahead with next steps. If not, check for other DTC’s presence.

Check whether similar complaints are earlier reported. If yes, perform the preliminary checks with respect to

earlier issue closure.

Ensure IMV connector is properly connected to the IMV.

Ensure there is no mud, dirt, foreign particle accumulation on the connector.